I just purchased a 2005 t300- ran the machine for 2days with no issues-I changed all the fluids-and filters including drive motor return and accesory filter with all bobcat products -motor oil filter, anti freeze and flushed 15 gallons of hydraulic fluid- The problem i am getting low pressure light-didnt have it untill changing fluid-I changed out the pressure switch with new-light still comes on at times-checked charge pressure at high idel with brake on - reads 350lbs- when switching brake off pressure is at 295lbs- Looking at service book pressure should be 370 to 430-has anyone ever increased charge pressure-with no help from local bobcat dealer-they want me to bring machine to dealer that is an hour away- Can someone please tell/ show me how to increase pressure or tell me what is wrong or what else to be looking for-thanks Rick
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I know that i did get air in system-I let the machine idle for two hours and raised lowered and bucket every 10 min-then trammed the machine back in forth-i ran the gauge into the cab so I can keep an eye on it-The pressure stays constant at 290 lbs while using the machine other than when i put the park brake on it increases 60 lbs- the machine runs perfect with plenty of power and no leaks-2000hrs-In the service book it states to buy a shim kit and add shims to increase pressure-i have no clue on where the charge relief valve is on this machine thanks for any ideas and help rick
the charge relief that those shims go in is on the back side of the Sunstrand , the is a big hex head plug in the middle section , if you never done this before it could be pretty rough for you as you can't really see whats going on and your working by feel , I would suggest putting down a clean white rag under the plug before you take it out as it is very easy to drop the many pieces that make up the relief as it is not a cartraige type -----------increasing the pressure with shims may help you for a while but I doubt that is your real problem , I would think the pressure is being lost though one or both of the brake packs of the travel motor ---------------did you do the case drain filter yet , I would do that before going any further and see how much metal is in it and what colors you get , it may give you some indication of whats going on --------------
I read your original post again and see you changed what you called the motor return filter , that term threw me off , I would still go in and check the case drain filter again and see whats in it , did your old hydraulic oil have a golden sheen to it , who ever sold it to you may have known it was on it way out , and the case drain filter may have be changed right before you got it , be sure you that you put the rock filter back the same way it is suppose to be with the cup side facing the inlet side of the filter casing , as if install backwards or it get over loaded with trash it will let the trash from a travel motor tearing up go thru your system and total out the hydrostatic and hydraulic system making the machine basically not worth repairing as you could easily sink 10-15 thousand into it and never get all the pieces of trash out the sytem and then tear it up again as it is like a blender grinding up all those little pieces ------------ from past experiences when the charge pressure drops it is not a good sign , I would think that if you have a deluxe panel and set it so you can monitor the charge pressure while you multi function the machine you will find charge presuure will drop down even further which will cause the machine to hydraulically bog down , and when it gets bad enough you will have to stop for a second for the charge pressure to catch back up to continue to operate while multi funtioning -----does the brakes hold the machine when you try and move against it ------- I hope not for your sake but it really sounds like the parliminary signs of a cathistrophic hydraulic failure
yes -thats is the filter i changed-the filter was about 40% clogged with silver flakes and looked like small black pcs hose-the machine has 2000 hrs on it-looking at connections and where filter comes a part in two-there were no wrench marks or and signs that it was ever apart before-dont think anything got past the filter-I ran the machine for a day after changing it and took it apart with no materials in the filter. The brake holds the machine-i have a gauge running into the cab-with the brake on i have 350lbs-when the brake is off it drops to 295-at fast idle while running the machine i never see it dropping any lower than that. the pressure sensor is set to go off on 300lbs
i also changed the hub oil-the fluid was a little dark-put it in a container with a magnet-no metal materials were found-replaced with bobcat fluid -measure the amount drained and was about the same going back in-dont know if this helps- could i be having a problem with bypass in the brakes
Biggie , Wonder how he ever made out , this is an old thread
Ya. Haven't been around to check out what's happen'n. It' s good to get a response back, to hear if u'r on the rite track?
If u r getting ANY light on the right side panel. u should be able to get the Code. LIGHTS/HOLD FOR CODES, or the"I" Button. That helps a ton. It,s probabley low charge psi. Could be just the sensor? Trouble codes r good to figure this out
